The present invention relates to field transmitters used for process control. In particular, the invention relates to field transmitters having selectable modes of operation.
Processing plants, such as chemical, petroleum, gas, and pharmaceutical plants require careful control and monitoring of a variety of process variables. Examples of process variables include pressure, temperature, flow, conductivity, and pH. To monitor process variables located throughout a processing plant, devices known as field transmitters have been developed. A field transmitter includes a transducer that responds to a measured process variable with a sensing element and converts the variable to a standardized transmission signal (e.g., an electrical or optical signal) that is a function of the measured process variable.
Depending on the application, a large number of transmitters may be required to monitor process variables throughout a processing plant. In addition, the application or functionality required of each transmitter may be different, depending on the application. To meet each of the variety of applications and functionality, a manufacturer typically offers a variety of unique transmitters, each providing different functionality and performance.